The long-awaited National Carp Control Plan (NCCP) has been delivered to the federal government but is yet to be released to the public.
The plan comes after years of delays and is meant to determine whether a carp herpes virus should be released into Australian waterways as a pest control method.
The Fisheries Research and Development Corporation (FRDC) assessed the feasibility of using the herpes virus Cyprinid to control carp in the Murray Darling Basin.
A herpes virus has previously devastated farmed carp stocks in the northern hemisphere and has long been considered to be the best option to manage the invasive species in Australian waters.
While initial testing has shown that the virus would be effective to control feral carp domestically, concern around the impact of dead carp on native ecosystems has been one of the main barriers to a wider spread release. Large volumes of rotting carp have the ability to reduce oxygen levels in the water which poses a significant threat to native fish species.
Some ecologists argue that the short term issues are a small price to pay for the longer-term ecosystem benefits that a carp-free system will bring.
“It will be very short-lived if there is a water quality problem and it will be for only one season for a lifetime of benefits,” said John Conallin, a freshwater fish researcher with the Institute of Land, Water and Society.
While the NCCP will make a recommendation on the use of the virus, individual state and territory governments and the federal government will all have to also agree in order for the virus program to go ahead.
Shadow agriculture minister David Littleproud, who oversaw the NCCP during the last government, said that Labor needed to make the report public sooner rather than later.
“I just have no idea why the Labor government won’t release the report immediately so everyone can see it, work through it, and have an opinion.”
“The interim recommendations the FRDC provided to me was the virus would eradicate around 96 per cent [of carp],” he added.
European Carp in Australia
Carp, which are native to central Asia, were originally imported to Europe where they became one of the most popular angling species. Early settlers in Australia imported them with the aim of recreating a European environment with the earliest carp introduction being recorded in 1859.
It is thought that carp have been in the Murray Darling Basin system since the 1920s, with a new species imported in the 1960s by an aquaculture farmer in Mildura. Flooding in the 1970s spread this new strain into the river system, and carp established populations in South Australia, New South Wales and Victoria.
With up to 1,000 fish per hectare, the river system has been significantly affected by the presence of European carp. As bottom feeders, carp are responsible for declines in water quality, reducing the amount of sunlight penetration required by native vegetation and fauna species, also competing with native fish for food and habitat.
Prolific breeders, a single 3kg carp can produce 3 million eggs in an average year.
Sources: ABC, Charles Sturt University, Department of Primary Industries.